One example of such coated paper is low ignition propensity wrapping paper for cigarettes.
In recent years, low ignition propensity wrapping paper for cigarettes has come to be widely known, and such wrapping paper has a fire retardant coated on (applied to) predetermined regions thereof. Where a cigarette using the low ignition propensity wrapping paper is lit, spread of fire toward the proximal or mouth end of the cigarette is restrained. Specifically, the low ignition propensity wrapping paper for cigarettes is obtained by applying a fire retardant in liquid form to a strip-shaped web of paper in such a manner that the regions applied with the fire retardant are spaced at predetermined intervals from each other in the longitudinal direction of the web and extend in the width direction of the web (like bands), and then subjecting the web to aftertreatment such as drying.
The low ignition propensity wrapping paper is often required to have bands of the fire retardant arranged at the intervals defined as a standard (hereinafter referred to as design band pitch). For example, where cigarettes to be produced require that the low ignition propensity wrapping paper to be used should have bands complying with the design band pitch, low ignition propensity wrapping paper having bands with an irregular band pitch or in disagreement with the design band pitch is rejected and is not used.
There has been known an apparatus which is configured to inspect the width and spacing of the bands of a fire retardant on the web in the process of manufacture of cigarette wrapping paper (Patent Document 1). Also, a cigarette paper manufacturing machine has been known in which the width of bands formed on the web is inspected by an inspection apparatus to adjust the amount of the fire retardant to be applied to form the bands (Patent Document 2).